Method of and apparatus for individualizing telephone time-signals



(No Model.) 2 Sheets-Sheet 1.

H. B. LYTLE 8c J. J. OAETY. METHOD OF AND APPARATUS FOR INDIVIDUALIZING TELEPHONE TIME. SIGNALS.

Patented June 3, 1884 74 i6ne55e A N. PETERS. Phnmliahu n ne (No Model.) 2 SheetsSheet 2.

H. B. LYTLE 8a.]. J. CARTY. METHOD OF AND APPARATUS FOR INDIVIDUALIZING TELEPHONE TlME- SIGNALS. No. 299,561. Patented-June 3, 1884.

77 367065565. 7 V Inn/67160715 HZYoT;)/ B,Lj/Z6, W W (707270 J'Gcw ty,

' QB) 621/67, attorney,

UNITED STATES ATENT Ulrich.

HENRY B. LYTLE AND JOHN J. OARTY, or BOSTON, MASSACHUSETTS.

METHOD OF AND APPARATUS FOR INDIVIDUALIZING TELEPHONE TIME-SIGNALS.

SPECIFICATION forming part of Letters Patent No 299,561, dated June 3, 1884.

Application filed JanuarylO, 1884. (No model.)

To all) whom, it may concern.-

Be it known that we, HENRY B. LYTLE and J GEN J. OAR'rY, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain Improvements in Telephone Ti1ne-Signal Distribution, of which the following is a specification.

Our invention relates to the distribution of standard time by means of the well-known telephone exchange system of subscribers wires and apparatus; and it consists more particularly in a method of individualizing the distributed time-signals in such a way that they may be supplied to such subscribers and over such subscribers lines as may be found desirable, while they may be rigidly excluded from lines that are not to be supplied. It consists, further, in certain specific instrumentalities and circuit arrangements in which the said method may be embodied and through which the desired result may be effectuated.

In Letters Patent No. 287,710, issued October 30, 1883, to John M. Oram, a method and apparatus are described. by which all of the subscribers of a telephonic system are furnished with correct time from a single standard clock by continuous signals repeated throughout all the minutes of the day. The method consists in interposing a battery and circuit-breaker in the common ground-wire of all the circuits of a telephone-exchange, and

in causing a clock, by means of suitable intervening mechanism, to operate the said circuitcloser in such a way that the hour and the exact number of minutes thereafter are successively repeated upon the circuit every minute of the day, and thus any subscriber on any wire desiring to be acquainted with the correct time to the minute has only to take his telephone from its support and put it to his car, when he will distinctly hear first the hour, and immediately thereafter the minutes after the hour. In practice, however, it has been ascertained that in many cases it is desirable to extend the facilities for the distribution of the time to a certain number only of the subscribers over their individual lines, and equally undesirable to extend the same facilities to others, and, for reasons which hereinafter appear, how to accomplish this has proved very problematical. It is usual to charge a small rental to subscribers receiving the time-signals regularly, and as many of the subscribers have no need of the time as corrected, and therefore do not care to pay any rental therefor, it is essential that an effectual plan should be devised whereby those not paying shall not receive the time. It would seem at first as though the problem of excluding the said time-signals from a portion of the subscribers lines would be easily accomplished by simply connecting the said lines to a separate and independent ground-wire not acted upon by the clock and circuit-breaker; but by reason of the extreme sensitiveness of the telephone as a receiving-instrument and the intensity of induction between parallel lines such is not the case.

It has been demonstrated by experience that if a definite number of lines are furnished with the time by the clock and circuit-breaker nearly every line radiating from the sfime central office will be the recipient of similar signals by induction, and this is especially the case in the more recent methods of construction, wherein the radiating lines are, for the first half-mile or so from the central station, conducted, for economy of space, through aerial cables, in which a number of lines are massed close together in a small space. It has also been demonstrated by experience that by our invention the time-signals may be readily con fined to the desired lines; and to this end our invention consists, first, in sending induced currents of a rhythm and number equal to the beats of the circuit-breaker and corresponding to the time at any given minute over the lines to be supplied; secondly, in sending simultaneously aconfusin g signal over the lines which are not to be supplied;- and, thirdly, in using separate ground-wires and switch-terminals,whereby every possible means for separating the two series of lines from one another are employed.

Our improvement is based upon the hereinbefore-cited patent of Oram, which, so far as we know, represents, prior to our invention, the state of the art, and to which reference may be made. Since the general plan of distributing the time has not been departed from in our invention, we do not regard it as necessary to rehearse it here, the changes and modifications which are essential being entirelyin the arrangement of the central-station apparatus and circuits, as we shall now describe.

Figure l of the drawings represents, diagrammatically, a series of the lines which are arranged to receive the time-signals. Fig. 2 is a similar diagram of the lines which are arranged in such a manner as not to receive the time-signals, but, in contradis'tinction thereto, to receive a confusing signal. Fig. 3 illustrates the mechanism by which the time-signals are transmitted to one series and the con fusing signal simultaneously to the other series of lines. Fig. 4 is an elevation of the special form of the annunciator shown in Fig. 1. Fig. 5 is a diagram exemplifying a modification of the method of transmitting the timesignals. Fig. 6 shows the arrangement of the two series of lines upon a central-station switchboard; and Fig. 7 shows the central-station annunciator provided with a polarized armature, whereby, when currents sufficiently strong to ring the subscribers bell are sent to line, the annunciator is prevented from being acted upon.

Referring, first, to Figs. 1 and 4, which are to be considered together, the main lines L are shown as each uniting its own sub-station s with the central station, S, where a number of lines center. Arriving at the said central station, each line is connected with the helices m m of its own annunciator A, and from thence, by wire 1, to the common ground-wire, g, and ground G. The annunciator is sh own in elevation by Fig. 4., and consists of a double electro-magnet mounted on a base, I). The entire spoolof one leg of the magnet, together with the half-spool m of the other leg, is included in the line-circuit. The lower helix or spool of the rear leg of the magnet is entirely insulated from the line-circuit, and is adapted to be included in and to form part of a separate and local circuit. The annunciator, as usual, is furnished with an armature, a, and a drop signal or tag, t, pivoted at p to the base I), and normally upheld by the engagement of the catch 6 at the front end of the armature with a notch or slit in its upper end, in a manner well understood. Under certain contingencies, to be hereinafter enumerated, the armature (6 will be preferably polarized, so asto respond only when the currents of a certain polarity traverse the coils m, and so as to remain inert when the coil It only is energized.

It will be understood that the office of the helices m m is to energize the annunciator by means of currents received from the substations, and thus to actuate the drop and produce a call-signal. On the contrary, the office of the helix h is to change the magnetic condition of the core of the electro-magnet, and thus by induction to generate magneto-electric currents in the main-line helices mm, and consequently in the main line itself, these induced currents corresponding in time and duration with a clock-operated circuit-breaker, and actuating the receiving device at the sub-station to repeat the time-signal.

The auxiliary or local helices h of any desired number of circuits'i. 0., those which are to be supplied with the time-signalsare included serially, as shown in the drawings, in the local circuit of the battery B. A circuit-closer, 0, holds this local circuit normally open; but a controlling wheel or roller, R, provided with the requisite number of spurteeth, is adapted to rotate, making a complete rotation between each minute and the next, and as each of the projecting teeth touches the spring 0 it depresses the said spring on the lower spring, 0, and momentarily closes the circuit. The circuit of the battery B may be traced as follows: from B by wire 4 to he lix h of the first annunciator, then by Wire 5 to the next, 6, to the third, and so on through all of the helices h, after which it continues by wire 7 to one side of the circuit-closer C, then by the opposing spring 0 and wire 8 to the other pole of the battery.

It will be observed that although we have shown and described the circuit-closer as holding the local circuit normally open, and closing it to effect the necessary magnetic changes, we may readily reverse this condition and maintain the circuit normally closed, effecting the necessary changes by opening it in correspondence with the spur-teeth i of the rotating cylinder R. lVe prefer, however, the open circuit form shown.

We propose to employ substantially the same devices for changing the time-signal in accordance with the evenchanging time of the several minutes and hours as that employed in the Orain patent, which we have hereinbefore referred to, and a portion of this device is the rotating cylinder, shown in Figs. 1 and 2 as the actuating device of the circuit-closers. It is fitted with spur-teeth or studs t in a manner resembling the arrangement of a musicbox. As shown in Fig. 3, the local circuit has in practice three circuit-closers, C, to which the respective main wires 7 and 8 of the local circuit are branched. The wire 7 is united to the upper spring of the circuit-closers by the branch wires 10, and the wire 8 is similarly united to the lower spring by the wires 11. To operate these circuit-closers there are three sets of studs, 6, on the rotating cylinder-via, one set representing the hours, and these in Fig. 3 are supposed to have already passed the left-hand circuit-closer, a second set representing the tens of the minutes, and these are shown as being in the act of passing the middle circuit-closer, only two or more teeth having now to pass, and a third set representing the units of minutes, which have not in the drawing yet reached the third circuit-closer.

It is obvious that, since the local circuit is normally open at all three circuit-closers, when the teeth or projecting studs 1' of the cylinder press down the spring 0 of any one of them, the circuit is closed for an instant until the stud releases the spring and passes onward. The operation of these devices may be briefly indicated: WVhen the circuit-closers are open, the annunciators A are inert. When the said circuit-closers have their springs c and 0 brought together by the impingement of the cylinder-studs i, corresponding to the hour and minute of the day, the circuit of the battery B is closed, and the current flows round the coils of the helix h, magnetizing the core and producing an induced current in the main-line coil m m. This passing over the line repeats the signal upon the telephone or other receiving-instrument when the said instrument is brought into the circuit. The signals sent of course correspond in number to the number of times the local circuit is closed at 0. Ordinarily the induced current isstrong enough only to repeat the signals to the subscriber by means of his telephone; but if it is desired that the signal shall be repeated on the bellD of the said subscriber, it is only necessary to increase the strength of the battery B. If, however, the induced current is thus made strong enough to repeat the signal upon the bell D, it is found also to be sufficiently strong to drop the annunciator-signal, which should respond only to the call of the subscriber. We avoid this by polarizing the armature a of the annunciator, as shown in Fig. 7, and by connecting the battery B so that its current will flow around the core of the annunciator, through the helix h, in such a direction as to produce magnetism in the said core and in the pole thereof of like polarity to that of the free end of the armature. The core then, instead of exerting an attractive power upon the armature, will repel it, and the drop-signal will not be actuated, while it is left perfectly free to respond to the alternating currents of the subscribers call.

WVe will now, referring to Figs. 2 and 8, describe the arrangement of the lines leading to such subscribers stations as are not to be supplied with the time-signals. The several lines L are fitted with bells D and telephones T, as usual, and, as in the former series, unite the sub-stations s with the cen tral station S. The annunciators A are of the ordinary pattern, and are not provided with the extra and auxiliary helix h or with the local circuit and battery. The several linecircuits each proceed from the sub-station ground G through the bell D and telephone T to the line L. Arriving at the central station, the circuit is continued through the annunciator-wire 3,co1nmon to the series. This connects, through battery 13, wire 12, circuitcloser C, and wire to ground at G. It is immaterial whether the battery B be placed inthe circuit at the point shown or whether it is included in the wire 9 between the circuit-closer G and the ground. The annunciatorAinthis case serves merely as an instrument to indicate the call of the subscriber, and is, as usual, provided with armature a and drop-signal t, controlled by the catch 6 at the end of the armature. The rotating disk R is affixed to the same axis as the cylinder R, and it may be a part thereof; or it may be, as shown in Fig. 3, a separate disk fastened upon the axis and insulated therefrom. It is by no means necessary that the rotating disk R shall be upon the cylinder-axis J; but I prefer so to place it for convenience of operation. The several spur-teeth or studs, 1', arranged round the periphery of the disk, may be continuous, as

shown, and adapted to actuate the circuitcloser continuously; or they may be attached only to a portion of the periphery corresponding in extent to the total extentover whichthe time-signal studs are arranged on the other portion of the rotating cylinder, so as to operate the circuit-closer only during the exact time that the time-signals are being sent. the impingement of the studs 2 upon the projecting portion of the spring lc,the said spring 'is caused to alternately break and close the circuit by its alternate connection and disconnection with the upper contact-point, 70. Like the local circuit-closer O, the main circuitcloser C may be reversed without impairing its eftectivenessthat is, it may in its normal condition be open, instead of closed; and this change may, when required, readily be made by any one skilled in the art.

The arrangement we have herein shown and described constitutes the means whereby the confusion-signal is sent over the lines which are not to be supplied with the time; and it may now be seen thatour plan, in general, for selecting certain lines for time-service and excluding other lines from the benefits thereof is to remove the ground-wire leakage and reduce the induction from wires conveying timesignals by preventing the ground-wire from being a factor in the case, and by originating the signals by means of an induced current, and, further, by sending simultaneously upon lines which are not to be served a confusing or obliterating signal, which will prevent any approximation to the time-signal from being heard.

WVe show in Fig. 5 a modified arrangement for time-signaling, which in some instances may be substituted for that shown in Fig. 1, and which operates by weak currents. The battery B is normally connected with the line L through the annunciator A; but it must be of such a degree of strength that it will not magnetize the magnet-cores to such an extent as to attract the armature and drop the signal. The clock E alternately closes and opens the local circuit, including a battery, 13*, and electro-magnet W, and this magnet, either directly or through the intervention of the rotating cylinder shown in Fig. 3, alternately breaks and closes a short-circuit round the main battery 13 via armature-lever 10, wire 14 wire 13, and contact-screw z, producing electrical variations upon the line, and thus giving the time-signals to the sub-stations.

In addition to the foregoing devices, we have found it advisable to provide separate ground-wires for the two series of wires. This arrangement is shown in Fig. 6. The lines L are all at the central station led to the switchboard II. After passing the said switch-board, such of the lines as are to be supplied with ti m c*the three, for example, on the leftmay be terminated upon the cross-bar 0, which, by the wire 11, battery B, and wire is connected with the ground, the battery, as in Fig. 5, being controlled by a clock, E, magnet W", and the shunt-circuit 13 and l l. The lines which are not to be supplied are connected with the lower cross-bar, q, and thence by wire through the circuit-closer G, to a ground terminal at a place distant from the first.

lVe do not confine ourselves to the exact and precise instrumentalities herein shown,

since it is evident that the principle which forms the essence of our invention may be varied greatly without being departed from, and that it is not dependent upon any particular form of apparatus. e may, for example, instead of attaching to the annuneiators auxiliary helices included in a local circuit and energized by a current varied in correspondence with the time-signals, use a reel, upon which the primary or energizing circuit is wound in one or more layers, and, interposing in the circuit of each a length of fine insulated wire, wind the said lengths of fine wire together upon the said reel over the primary wire. In the employment of this device a core of iron would ordinarily not be essential, unless very strong currents are desired.

Having now described our invention, we claim- 1. The hereinbefore described method of regulating or individualizing the supply of time-signals to the subscribers of atelephoneexehange system by producing induced currents corresponding to the timesignals in the line-circuits to be supplied, and simultaneously sending a confusing signal or succession of signals over the line-circuits which are not to be supplied.

2. The method herein described of compensating for the involuntary distribution of timesignals by induction and leakage over tcle phone-circuits which are not intended to receive the same, which consists in transmitting over the said circuits a confusing or obliterating signal, whereby the induced time-signals are confused and made incomprehensible.

3. The method hereinbefore described of producing induced currents corresponding to time-signals in a series of telephone line-circuits, which consists in passing battery-currents equal in number and duration to the said time-signals through a series of helices (one for each line) placed on the core of the annunciators of the said telephone line-circuits, and in juxtaposition to the helices thereof, substantially as specified.

4. The combination,in a telephone-exchange system, of a series of main lines and centralstation annuneiators therefor, the said annunciators each being provided with an extra helix, a local battery-circuit including the said helices, and a circuit-closer for said local circuit adapted to be operated by a clock-actuated time-cylinder, and to send time-signals to line, with a second series of main lines and a battery and circuit-closer in the main groundwire thereof, the said circuitcloser being adapted to alternately make and break the circuit of the said battery and ground-wire during the time of transmission of time-signals over the first series of lines, for the purposes specified.

In a tclephone-exchange,a time-transmitting system therefor, consisting of the combination of a series of main lines, receiving-instruments at the respective sub-stations of the said main lines, an annunciator for each line at the central station. an auxiliary helix placed on each of the said annunciators, a local battery, a local circuit including the battery and the said auxiliary helices, and a circuitcloser actuated by a rotating cylinder and arranged to close the circuit under the influence of the said cylinder a number of times corresponding to the hour and minute, whereby currents of similar number and character may be induced in the main lines and the timesignals reproduced in the receiving-instruments thereof, substantially as described.

6. The combination, substantially as described, with a main telephone-line and a substation bell included therein, of the hereinbefore-described time-transmitting devices, consisting of the local battery, circuit-closer, timerepeating cylinder, auxiliary annunciator-helix, and the annunciator, provided, as described, with a polarized armature, whereby when the actuating current is strong enough to ring the bell it is prevented from giving the annunciatorsignal.

7. The combination, in an electric annunciator, of an electro-magnet provided with two separate helices, the larger of the said helices being adapted for inclusion in the main line, and the smaller in a local circuit, and a polarized armature therefor adapted to respond to the magnetism of the eleetro-magnet when induced by the main-line helix, but not when induced by the local circuit, as described.

8. The combination, with a series of telephone-lines, of aseries of local circuits arranged in inductive proximity to a portion of said main lines, and adapted to generate induced currents therein, a series of local circuit closers adapted to open and close the said local circuit-s, aseparate circuit-closer included in the common groundwvire of the remaining portion of the series of main lines, and a revolving clock-controlled cylinder actuating the said circuit-closers, and adapted to In testimony whereof we have signed our close the local circuit-closers in correspondnames to this specification, in the presence of once with time signals, and simultaneously two subscribing Witnesses, this 31st day of De- 15 open and close the main-line circuit-closer cember, 1883.

, 5 without reference to time, for the purposes specified. HENRY B. LYTLE.

9. In combination with a'series of telephone- JOHN J. CARTY.

lines and time-transmitting signaling apparatus fora portion of the said lines, means, Witnesses:

10 substantially as described, for sending a con- GEO. WILLIS PIERCE,

fusing signal over the remainder of the said D. E. RICHARDS. telephone-lines, for the purpose specified. 

